The slider has lots of flexability. It really works like a row you can split into columns and do what you like.
You can drag the bottom of the slider down to increase its height.. this what you are after..?

It would be awesome if one of the image/slider options for sizing would allow displaying the image(s) at full width and automatically adjusting the height to show the full height of the image even in a responsive environment (see attached screen shots for an example of a slider we have been using that does this). This allows the full image to be seen regardless of the device screen size as it just proportionally scales the image/slider up/down as it isn't always practical to have parts of the image/slider hidden based on screen size or break points.

This would have to be a competely different implementation of the current slider,
Being the current slider allows multiple rows and columns and is quite flexible , we would need to implement a simple version.. Basic image upload ( which sets height) and some basic text fields you can edit..

so do you know how to change the size of the images that we put in the slider? Also, do you know how to set products to go in multiple categories. Like a ladies T-shirt. I would like it to appear in my products under 2 categories, T-Shirts and Ladies (a new category I want to make)
Thank you

So I think what you are after are the settings for how to display thebackground image.

If you hover over the slider , you will see a green tab in top left hand corner of slider with text "Slide 1 of 3", next to this is a dropdown arrow.
If you click the dropdown and go to panel settings , this will load the settings for slide 1. ( repeat for slide 2 and 3).

When the popup opens you can go to background properties tab.

Here you will see all the standard ways you can choose to fill / repeat / size the background image. (Cover / contain / stretch / Original)/

For best results your image should be created so it has the same aspect ratio as the slider itself, this way it will fill perfectly and shrink down resposnively perfect for mobile mode.